Aeroplane



0. R. WITTEMANN.

, AEROPLANE.

APPL CATION FILED FEB.24,1915. 1,341,029. Pate ted May 25, 1920.

I Q 3 SHEETSSHEET 1.

r Z? 25 16 1.9 A 2, 12 1.9 25 gig .3

5 vwamfoz C. R. WJTTEMANN.

AEROPLANE. APPLICM'ION FILED FEB. 24, 19:5.

Patented May 25, 1920.

3 SHEETS SHEET 2.

C. R. WITTEMANN.

AEROPLANE.

APPLlCATION FILED FEB: 24, 1915 Patented May25, 1920 3 SHEETSSHEET 3.

UNITED .s'rA'rss PATENT OFFICE;

CHARLES R. WITTEMANN, OF RICHMOND, NEW YORK.

AEROPLANE.

Specification of Letters Patent.

Patented May '25, 1920.

Application filed February 24, 1915. Serial No. 10,200.

This invention relates to aeroplanes, and

my improvements are directed to a certain novel construction and arrangement of parts therein whereby inherent stability is served and the etliciency of a heavier-thanair flying machine enhanced both as regards its lifting power and steadiness in flight.

Broadly stated, the general character of my improved machine involves the employment, in an aeroplane structure, of a series or plurality of supporting aerofoils in spaced horizontal relation, with alternate aerofoils occupying different vertically spaced horizontal pressure areas, the purpose being that the area of pressure resist ance of the foremost supporting aerofoil in each horizontal pressure area, may not exercise disturbing influence upon the next following supporting aerofoil in the same v horizontal pressure area, because the latter is located a sufficient distance to the rear of the area of said foremost plane, to be beyond the aerial disturbance created thereby, and thus enabled to meet a succession of nearly undisturbed atmospheric supporting columns in the direction of travel of the machine.

Succeeding acrofoil units may be added as required, in each horizontal pressure area, in the same relative arrangement, according to the degree of lift required.

Since the angle of attack of a supporting aerofoil, at a given speed, as well as the extent of its chord, and the degree of camber it possesses, all contribute to vary the extent of the rearward disturbed pressure area, which detracts from the support afforded a succeeding aerofoil surface, I have found by experimentation that it is possible through a consideration of the factors stated, to practically determine the distance apart at which a followingaerofoil should be placed to be beyond the main zone of aerial disurbance of the forward aerofoil. Hence, by this arrangement, the following aerofoil surface will meet almost, if not quite, the same degree of pressure resistance as the forward aerofoih The followin aerofoils, in each horizontal ar ea, may a ternate in their following arrangement, so that the aerofoils in the upper horizontal area may be disposed each above a space separating two adjacent aerofoils of the lower horizontal area.

Although conceivably single supporting plane surfaces may be employed as serial units of my improved structure, in the manner of a monoplane, yet I consider it desirable, on account 'of the greater structural strength and rigidity provided, to compose the units each of superposed planes in the manner of a bi-plane. The example of aircraft presented in this application as embodying my improvements is therefore inclicated with its units of the bi-plane type,

though I do not intend thereby to limit myself to that character of supporting unit.

In the usual single unit aeroplane, whether monoplane or bi-plane, the center of pressure is constantly varying in ascent or descent, or in banking; thereby, under certain conditions, tending toward a loss of equilibrium which niaycapsize the machine.

But, with an air-craft of the multi-unitplane character described. this tendency is considerably reduced, because, with the shifting of the center of pressure and consequent reduction of uppermost pressure area in the machine, a factor of safety is provided in that so much greater 2. lowermost pressure area is provided to counteract the tendency toward loss of balance. Furthermore, with a machine of the character I have described, having three, five, or other uneven numbers of supporting units, in the spaced relation set forth, each unit having its own center of pressure, it will be apparout that the central supporting unit serves as a common or turning center longitudinally for the entire structure, with the advantage, in inherent stabilization, that the efiectsof undue pressures against the supporting units at either side thereof, are neutralized by its own pressure receiving surface and the surfaces of the supporting units at its other side. Similarly, with even numbers of supporting units, the same result will be attained, excepting that there Will be no central supporting unit as a turning center.

Usually with single supporting unit aeroplanes the increase of head resistance will advance the center of pressure, tending to elevate the machine, but by the use of a folw supporting pressures probably exists with relation to the aerofoil units succeeding the foremost unit, notwithstanding the arrange ment of multi-unit-planes described, I may provide in increasing the lifting power proportionately of the succeeding units, as by increasing their length, each succeeding aerofoil unit being longer than the preceding one, to thereby compensate for the loss inpressiire by an increase in, the capacity or" the pressure supporting area presented.

Without being so limited the central supporting unit may coincide approximately with the vertical axis of 'the center of gravityof the machine, whose stability, it will be appreciated, cannot fail to be further augmented by such arrangement, and to be effective both as regards lateral and longitudinal balance.

I may however also employ stabilizing de vices, either rigid or movable, placed preferably' at the ends of the supporting units, or some of them, to still further assure proper stabilization.

In a machine of my improved type, having three of the spaced supporting units referred to, I may employ propellers with their motors for the first and second units, and, where five units are included in the aeroplane structure, I may add a third propeller or pair of'propellers, or tractors, with motor; in conjunction with the fourth sup porting unit. The arrangement and number of power plants suggested is however more or less arbitrary and open to such modifications as may be found desirable in special cases.

It will be quite apparent that my improvements thus far disclosed are applicable equally to machines capable of rising from and alighting upon either land or water.-

But in this applicationl also include a certain novel. formation of boat, which, with an improved fuselage and'prow, all combine to produce a flying boat of highly eflicient character.

My improved boat includes in its design a rearwardly stepped bottom whose recesses or steps break the continuity of the bottom surface longitudinally, whereby, both when traveling in the water and through the air, frictional resistance reduced by the rare faction effected at the several steps. while the rear portion oi the boat may taper o'ii into stream lines for the purpose of facilitat ing passage through either element.

The frame of the dying machine may cousist of parallel longitudinal burs arranged.

in quadrature through the horizontal area.

of the lower ticroi'; supporting units, said bars being braced as by vertical and trans verse struts, reinforced by angular-1y drawn wires, and said frame including a covered in fuselage. Also, projecting outwardly and pockets will increase with the acceleration of speed in flight of the machine through the air.

Other features of invention and details oi .-onstruction will hereinafter appear.

In the drawings accompanying this application: i

Figure 1 is a side view in elevation of my improved hydroaeroplane, it being here shown as including live supporting plane units.

2 is a top plan view thereof, on a larger scale.

Fig. 3 is a front elevation, and

Fig, 4: is aperspective detail, showing the frame root construction.

in the example of my invention illustrated herewith I have shown a series of five longitudinally spaced supporting plane units, these being represented, respectively, in their order of arrangement from front to rear, by

the numerals 1, 2, 3, 4 and 5, the units 1,-

3 and being located in a horizontal area intersected by a. supporting frame, and the units 2 and 4 being supported above said frame. The said frame may, as shown, he composed of the longitudinal bars. 6. arranged in quadrature, and connected by struts and braces 7, reinforced by theangu larly drawn wires 8; and said frame, or a portion thereof, may be inclosed, as bv the walls 9, to form a fuselage. v

The supporting plane units are here shown as bi-planes, but may, for the purposes of my invention, consist of a single plane each. or of more than two planes. For convenience of description I call them supporting units.

The intervening distances separating udjaccnt units in a like horizontal pressure area are of an extent which is governed by the speed at which the machine is designed and powered to travel and the particiilar pressure disturbing characteristics of said units, the sum of these factors determining the area or" ores-sure disturbance atthe rear of each unit, from the influence whereof it desirable to unit, in order may meet themsximum supporting presure available.

of a iorwar remove the next following that the latter, in .its 'turn,'

a, way of example, the distance separat ng the rear or trailing edge have different characteristics, which cause them, in the flight of the machine, to have greater or less disturbing influence upon the air from which they receive support. For example, when building an aeroplane of the character. indicated in this application, in which it is desired to arrange the following aerofoils in such manner that each will meet approximately the same supporting pressure, applicant has worked out a machine in which the respective aerofoils have a chord of six feet, attacking angle of 4, camber of 2%", and the machine to be propelled at about 80 miles an hour as its most efiicient speed. Under these, conditions and following the formula which he has deduced, applicant finds that the following planes will be separated from each other by about 30 feet, that distance behind an attacking aerotoil serving to neutralize the aerial disturbance created by said attacking aerofoil with respect to the nugatory influence thereof upon the following aerofoil, so that, at the stated distance of 30 feet, or thereabout, rearwardly of the attacking aerofoil, there is a resumption to approximately normal pressure, thus affording about the same support to the following aerofoil as to the preceding aerofoil. Despite this' precautionary arrangement in spacing the series of iollowing unlts, some loss in pressure support will occur, in increasing ratio for succeeding units, and I may therefor give said units, in succession, added pressure areas, as by elongating the aerofoils of said units, in proportionate ratio,--2 being longer than 1, 3 than 2, and so on.

The elevator plane, as 10, also the vertical rudder 11, are here shown as mounted on the frame at the rear thereof, these elements having no novel characteristics.

The frame, and also the boat, may have a slight rearward taper, horizontally, starting from an intermediate point in the length thereof, as at 12, to afford a desirable stream-like formation.

Also, the prow or forward portion of the boat may have a forward taper, to reduce head resistance. 7 i

The upper part of the boat prow, forming the head of the aeroplane, may be composed of a pair of vertical stabilizer plates arranged in such manner that their horizontal section is in form of a prone V, pointing forwardly and extending and curving rearwardly and outwardly, to reduce head resistance, and at the same time institute in the machine head a measure of balance restoring quality, to thus assist in the general scheme of inherent stability.

The said stabilizer head plates, as 13, may have each a forward curvature at their rear upper portions, whose function, when subjected to increased pressure at one side, is to release that pressure in the tendency it has to overbalance the craft from the increased pressure side, and to accentuate the pressure resisting character of the plate on the low or other side of the craft.

The plates 13 may have port holes 14 with transparent coverings to serve as observation openings for the pilot.

The boat bottom may be provided with a keel, as 23, to steady it in the water, and side auxiliary floats or pontoons, .as 16, may also be provided, to assist in floating the craft on an even" keel in the well known manner.

T he boat hull. may be constructed of wood laminations, arranged diagonally, as indicated at 17, while, as shown at 18, the hull structure maybe braced with vertical and diagonal struts and braces.

Exteriorly of the boat its bottom may be formed in a series of longitudinal steps, produced by the slightly downward, rearward inclines 19, each having their inception from a relatively forward recess or shoulder 20, whereby a series of rarefaction pockets are formed in the travel of the craft, either through water or air, to avoid some of the surface or skin frictional resistance which retards motion.

Under the pocket or cavity arrangement noted the boat bottom, in flight of the craft, will be subjected to skin friction only at the low points thereof antecedent to said cavities, when the speed is at maximum, because rarefaction will occur in said cavities due to the abrupt or vertical angle of the shoulders 20 and the downwardly advancing inclination of the steps 19 toward the perimeter of the succeeding shoulder.

The top of the longitudinal frame work, including the fuselage, may be roofed over, either partially or throughout its length, and as seen in Fig. 4, said top cover or roof may be concaved longitudinally, with its forward end closed, forming a lengthwise trough 21, to thereby decrease the downward pressure, by furnishing a channel of rarefaction in the line of flight over the longitudinal portion of the frame.

Plates or fins 22 may be placed, spaced apart along the frame, at opposite sides thereof, said plates being inclined outwardly and rearwardly from said frame sides to form rarefaction cavities vtherealong, for substantially the same purpose as the steps or cavities along the boat bottom. That is to say, in flight of the machine, said fins deflect the pressure of air, diminishing the degree of skin. friction operating upon the frame sides, according to the size, angle, and number of said fins employed and the velocity of rnoven'ient either of the machine through the air, or of the air pressure past the machine.

It is withinthe province of the designer, in building an air craft of the character herein described, to vary the angles of attack of the different pressure supporting aerofoils or units therein, to in that manner assist in promoting the acquireinent of the maximum of lifting eliiciency'for the machine, it being ajnnreciated that with an aeroplane comprising a, succession of spaced following aerofoils, according to their surface areas and separating distances, variation in the attacking angles thereof may well prove an auxiliary efiiciency factor.

' Also, the setting ol? the propellers may be so arranged in dili'erent horizontal areas that their lines of thrust both above and below the center oi g'avity may prove most eifective,

Variations may be resorted to within the spirit and scope of my invention, and parts thereof used without others.

1 claim:

1. An aeroplane having more than two lougitiulinallv separated suppoitin units, and comprising lined planes wherein each rcarwa rd unit is positioned relatively to the next; forward unit just beyond the area occupied by the rum-supporting disturbed air current which leaves said forward unit: the factors of chord, camber and angle of-said forward unit. in normal [light oi the aeroplanc, determining the extent of said disturbed area; \\'hercb v,said rearward unit l'nccts' approximately the samesupporting pressure as said l'orward unit.

2. An aeroplane bavinp more than two SQPiU'Htkll,SHPPUI'lHQ units,including a centrally disposed unit. to lorm a liked turning router for the acroplanc, and comprising fixed planes wherein each rearward unit is positioned relatively to the next forward unit just beyond the are; wcupied by the non-supporting disturbed air current which leaves said forward unit; the factors. of chord. camber and angle of said forward unit, in normal flight of vthe aero 'llanc, determining the extent of said disturbed area, whereby said rearward unit nieets approximately the same supporting pressure as said forward unit.

3. An aeroplane iaving a plurality of series of longitudinally separated supporting units, each series being arranged in a different horizontal area. and comprising fixed planes wherein each rearward unit in a series is positioned relatively to the no forward unit just beyond the area occupied rename by the non-supporting disturbed air current which leaves said for "aid unit; the factors of chord, camber and angle of said preceding unit, in normal flight of the aeroplane, determining the extent of said disturbed area; whereby the units in each series meet approximately equal supporting pressure; the units of the upper series being centrally disposed, respectively, with relation tosucceeding units of the lower series.

4. An aeroplane having a number of longitudinally separated supporting units, and comprising fixed planes wherein each rearard unit is positioned relatively to the next forward unit just beyond the area occupied by the non-supporting disturbed air current which leaves said forward unit; the factors of chord, camber and angle of said forward unit, in normal lli ht of the aeroplane, determining the extent of said disturbed area; whereby said rearward unit meets approximately the sanie supporting pr ssure as said forward unit; and a supporting unit dis posed in a separate horizontal pressure area in the vertical axis of the center of weight, to form a fixed turning center for the aero plane 5. An aeroplane having an uneven number of supporting units arranged in followin; order in the same horizontal area, wherein earn succeeding unit is located, relatively 'to its next )reccdiin unit, beyond the area occupied by the noinsupporting disturbed air currents \\'li!('ll leave said precmunp unit,

the factors of chord camber and un le of said forward unit, in normal llight of the aeroplane. determining" the extent oi said disturbed area; whereby the following units nicet a 1 ro:\'in'iat'cly the same supporting pressure as the forward units, the central unit being: in the vertical axis of the center of weight, to form a fixed turning center for the aeroplane; together with an even number of supporting units disposed in a separate horizontal area, and respectively lying between the vertical axes of succeeding units of the uneven series.

6. An aeroplane having a: longitudinal frame, supporting units mounted thereon, a vertical rudder, and a horizontal rudder, the supporting units comprising fixed'planes arranged in separate, horizontally disposed series, the units of one series alternating longitudinally with the units of the other series, and succeeding units in each series being positioned each relatively to anext forward unit just beyond the area occupied by the non-supporting disturbed air current which leaves said forward unit; the factors of chord, caniber and angle of said forward unit in normal fight of phe aeroplane, determining the extent of said disturbed area, to permit said units to meet approximately equal'supporting pressure; the central supporting unit of the aeroplane lying in the" aeaacaa vertical axis of its weight, to form the turn ing center therefor.-

7. An aeroplane having more than two longitudinally separated supporting units the distance between succeeding units bearing the relation of not less than four times the chord of a forward unit, in normal flight, said distance increasing in proportion to the increase of the camber and angle of incidence of said forward unit, whereby a rearward unit meets approximately the same supporting pressure as a forward unit.

8. An aeroplane having more than two separated supporting units, including a centrally disposed unit, and wherein the distance between succeeding units bears the relation of from four to six times the chord of a forward unit, in normal flight, said distance increasing in proportion to the increase of the camber and angle of incidence of. said forward unit, whereby a rearward unit meets approximately the same support- .ing .pressure as a forward unit.

' 9. In a flying machine comprising a longitudinal frame carrying a pressure supporting unit. the combination of a head portion composed of a pair of vertical plates whose plan formation corresponds to a proneV, the iipperreai portions of said plates being forwardly curved, to respectively assist in compensating for balance disturbing pressures.

10. An aeroplane having a series of transverse pressure supporting units arranged in following order in the same horizontal area, each succeeding unit being spaced beyond its preceding unit to clear the main area of rarefaction created by the latter, and the successive rearward units being of increased lateral extent, to each supply a greatefsupporting surface than the preceding unit, whereby compensation is provided for the diminution in supporting pressure due to the aerial disturbances created by forward units.

Signed at the borough of Manhattan, in the county of New York and, State of New York, this 23rd day of February, A. D. 1915.

CHARLES R. NITTEMANN. Witnesses:

F. W. BARKER, EDWARD Dnranr. 

